Acute and chronic conditions such as pain, arthritis, sleep apnea, seizure, incontinence, and migraine are physiological conditions affecting millions of people worldwide. For example, sleep apnea is described as an iterated failure to respire properly during sleep. Those affected by sleep apnea stop breathing during sleep numerous times during the night. There are two types of sleep apnea, generally described in medical literature as central and obstructive sleep apnea. Central sleep apnea is a failure of the nervous system to produce proper signals for excitation of the muscles involved with respiration. Obstructive sleep apnea (OSA) is caused by physical obstruction of the upper airway channel (UAW).
Current treatment options range from drug intervention, non-invasive approaches, to more invasive surgical procedures. In many of these instances, patient acceptance and therapy compliance is well below desired levels, rendering the current solutions ineffective as a long-term solution.
Implants are a promising alternative to these forms of treatment. For example, pharyngeal dilation via hypoglossal nerve (XII) stimulation has been shown to be an effective treatment method for OSA. The nerves are stimulated using an implanted electrode. In particular, the medial XII nerve branch (i.e., in. genioglossus), has demonstrated significant reductions in UAW airflow resistance (i.e., increased pharyngeal caliber).
Implants have been used to treat other conditions as well. For example, stimulation of the vagus nerve is thought to affect some areas in the brain prone to seizure activity; sacral nerve stimulation is an FDA-approved electronic stimulation therapy for reducing urge incontinence; and stimulation of peripheral nerves may help treat arthritis pain.
While electrical stimulation of nerves has been experimentally shown to remove or ameliorate certain conditions (e.g., obstructions in the UAW), current implementation methods typically require accurate detection of a condition (e.g., a muscular obstruction of an airway), selective stimulation of a muscle or nerve, and a coupling of the detection and stimulation components. Additionally, attempts at selective stimulation have focused on activating entire nerves or nerve bundles. A need therefore exists for an apparatus and method for selectively activating only the portion of the nerve responsible for activating the desired muscle or muscle groups while avoiding activation of unwanted muscles or muscle groups.
Accordingly, the present invention is directed to an apparatus, system, and method for selective stimulation that substantially obviates one or more problems due to limitations and disadvantages of the related art.